US officials are investigating Teva Pharmaceutical Industries over potentially illegal marketing practices for two of its key medicines.   

The Israeli drugmaker said it has received a subpoena from the Justice Department seeking documents and information spanning back to 2006 relating to the sales, marketing and promotion of its multiple sclerosis drug Copaxone (glatiramer acetate) and Parkinson's disease therapy Azilect (rasagiline). 

According to its filing to the US Securities and Exchange Commission, the government is investigating possible civil violations of the federal False Claims Act.

Teva also said it is "in the process of complying with the subpoena," but provided no further information.

With sales of more than $1 billion a quarter, Copaxone is the firm's number one selling drug, but analysts don't seem to worried over the impact the probe may have on Teva's bottom line.

“It’s hard to know at this point just how significant the case is,” Bloomberg reports Jonathan Kreizman, head of research at Bank of Jerusalem. “But typically these type of cases, if they lead to financial settlements, are seen by investors as one-time events and so shouldn’t be a huge hit for the stock," he noted.